The Naval Space Surveillance System was developed by the Naval Research Laboratory (NRL) during the period 1958 to 1964. This system was necessary to satisfy the needs of the U. S. Government's desire to detect nonradiating space objects passing over the continental United States (CONUS). This system has been operational since 1960 and is the only Navy system contributing to the Space Detection and Tracking System operated by the Space Defense Center, North American Aerospace Defense Command. This system, with no prior information, detects all objects in Earth's orbit passing over CONUS and computes the orbital elements of these objects. This report describes the design of the data communications system that was developed as part of the modernization program for improving the performance of the original Naval Space Surveillance Receiver Systems. Salient aspects of the design include increased data throughput, failure-recovery transmission modes, and message formatting characterization to satisfy the special requirements for system operation at Naval Space Surveillance Headquarters. The design also emphasized an abundant margin of data space for the control and text fields that were nearly exhausted at the completion of the developmental tests.